Crucible and method of making crucibles



June 7, 1949. J, ANlCETT] I 7 2,472,456

CRUCIBLE AND METHOD OF MAKING CRUCIBLES Filed March 20, 1945 Faber J.Anice f n Jatented June 7,1949

CRUCELE AND METHOD OF MAKING CRUCIBLES Robert J. Anicetti, Beverly,Mass, assignor to the United States of America as represented by theUnited States Atomic Energy Commission Application March 20, 1945,Serial No. 583,789

l I This invention relates to improvements in crucibles and methods ofmaking crucibles. More particularly, this invention relates toimprovements in crucibles and methods of making crucibles in which thebottom members may be replaced.

The general practice of molding or fashioning crucibles with the sidewalls integral with the bottom members, forming discharge outlets andfinishing and hardening the crucibles in a furnace or kiln presents manydifiiculties as the operation requires skill and takes considerabletime. Also crucibles formed in this manner have disadvantages, animportant one being that if the bottom of a crucible is damaged theentire crucible must be scrapped.

The method that comprises the present invention may be readily carriedout and if a bottom member of a crucible made in accordance with thepresent invention is damaged the bottom member may be removed from themember forming the side wall and the side wall fitted with anotherbottom member.

Accordingly the principal object of the present invention is to provideimprovements in crucibles.

and methods of making crucibles.

Another object of the present invention is to provide improvements incrucibles and methods of making crucibles in which the bottom membersmay be readily replaced.

Other objects of the invention will be obvious and others will beapparent from the following description and accompanying drawing.

In the drawing:

Figure l is a vertical sectional view taken through the center line of aform of crucible embodyin the invention.

Figure 2 is a vertical sectional view taken through the center line ofanother form of crucible embodying the invention.

The method of making a crucible in accordance with this inventioncomprises forming a separate side wall member from a length ofcylindrical tube or pipe made by molding graphite or other suitablematerial into a tube or pipe and finishing and hardening by firing in afurnace or kiln or by drilling or coring the cylindrical tube or pipefrom a finished and hardened block of suitable material such as agraphite electrode. A portion of the inner wall of the tube adjacent oneend is machined. formed from a relatively fiat disc-like member ofgraphite or other suitable material that has been finished and hardenedby firing in a furnace or kiln Suitable discharge outlets are formed inthe bottom member and the surface that forms A separate bottom member is19 Claims. (0]. 2.6 348) the upperside of the bottom member is machinedso that it slopes toward the discharge outlets to enable molten metal tobe completely drained from the crucible. The lower side of the bottommember is flat. The periphery of the bottom member is machined so thatthe bottom member may be pressed into the end of the member forming theside wall with its periphery engaging the machined portion of the innerwall of the side wall member with a machine fit. The area of contact ofthe bottom member with the side wall member is substantially equal tothe peripheral area of the bottom member and with the machine fit issufiicient to retain the bottom member in the side wall member withoutthe use of flange means or the like at the periphery of the bottommember.

With this method the side wall members and bottom'members may be easilymade as separately finished members and then fitted together to form thecompleted crucible. If during use the bottom member is damaged, thebottom member is replaceable by either removing the bottom member or bycutting ofi the side wall member above the bottom member, machining theinner wall of the side wall member adjacent one end, and pressinganother bottom member into the machined end of the side wall member. Theside wall member will outlast several crucibles made in the ordinarymanner.

Referring to Figure 1 of the drawing, reference character I indicates aside wall member compris-. ing a finished and hardened length ofcylindrical tube of graphite or other suitable material having an innerwall 2. A portion of the inner wall adjacent one end is machined to alarger dimension 3 forming a shoulder t. A finished and hardeneddisc-like bottom member 5 of graphite or other suitable material isprovided with a discharge outlet. fitted with a bushing 6. The uppersurface of the bottom member is machined to slope toward the dischargeoutlet as shown at l. The lower surface 8 of the bottom member is flat.The periphery of the bottom member is machined and the bottom member ispressed into the side wall against the shoulder with its machinedperiphery engaging the machined portion ofthe inner wall of the sidewall member with a machine fit. The area of engagement of the peripheryof the bottom member and the machined portion of the side wall and thecloseness of the fit are sufiicient to securely retain the bottom memberin position in the side wall member.

Referring to Figure 2 of the drawing in which is shown anotherembodiment of the invention reference character It indicates a side wallmember comprising a finished and hardened length of cylindrical tube ofgraphite or other suitable material having an inner wall II. A portionl2 of the inner wall adjacent one end is machined to form a slighttaper, of the order of several thouaandths per inch. The taper as shownin the drawing is exaggerated to illustrate this feature.

A finished and hardened disc-like bottom member member is machined tothe same taper as themachined portion of the inner wall of the side wallmember and the bottom member is pressed into the side wall member withits tapered periphery engaging the tapered portion of the side wallmember with a machine'fit. The inner wall of the side wall member ismachined to a suflicient length to permit the entire machined peripheryof the bottom member to engage it. The area of engagement of theperiphery of the bottom member with the side wall member, the degree oftaper, and the closeness of the fit are sufiicient to securely retainthe bottom member in the side wall member.

While preferred embodiments of the invention have been shown it is to beunderstood that changes and variations may be made without departingfrom the spirit and scope of the invention as defined in the appendedclaims.

What is claimed is:

l. The method of making a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and finished tube, forming a separate bottom memberby machining the periphery of a hardened and finished disc-like member,and pressing the bottom member into the side wall member with themachined periphary of the bottom member securely engaging the machinedportion of the inner wall of the side wall member with a machine fit.

2. The method of making a crucible comprising forming a separate wallmember by machining a portion of the inner wall adjacent one end of alength of hardened and finished tube, forming a separate bottom memberby machining the periphery of a hardened and finished disc-like memberand pressing the bottom member into the side wall member with themachined periphery of the bottom member securely engaging the machinedportion of the inner wall of the side wall member with a machine fitover an area of contact suflicient to securely retain the bottom memberin position.

3. The method of making a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and finished tube to a larger inner dimension,forming a separate bottom member by machining the periphery of ahardened and finished disc-like member and pressing the bottom memberinto the side wall member with the machined periphery of the bottommember securely engaging the machined portion of the inner wall of theside wall member with a machine fit.

4. The method of making a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and'finished tube to 9.

larger inner dimension, forming a separate bottom member by machiningthe peripheryof a hardened and finished disc-like member and pressingthe bottom member into the side wall member with the machined peripheryof the bottom member securely engaging the machined portion of the innerwall of the side wall member with a machine fit over an area of contactsufilcient to securely retain the bottom member in position. I 5. Themethod of making a crucible comprisi forming a separate side wall memberby machining a portion of the inner wall adjacent one end of a length ofhardened and finished tube to a larger inner dimension and forming ashoulder therein, forminga separate bottom member by machining theperiphery of a hardened and finished disc-like member, and pressing thebottom member into the side wall member against the shoulder with themachined periphery of the bottom member securely engaging the machinedportion of the inner wall of the side wall member with a machine fit.

6. The method of making a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and finished tube to a larger inner dimension andforming a shoulder therein, forming a separate bottom member bymachining the periphery of a hardened andfinished disc-like member, andpressing the bottom member into the side wall member against theshoulder with the machined periphery of the bottom member securelyengaging the machined por tion of the inner wall of the side wall memberwith a machine fi=t over an area of contact sufli cient-to securelyretain the bottom member in position.

'7. The method of forming a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and finished tube to form a taper, forming aseparate bottom member by machining the periphery of a hardened andfinished disc-like member to substantially the same taper as themachined portion of the side wall member, and pressing the bottom memberinto the side wall member with the machined periphery of the bottommember securely engaging the machined-portion of the inner wallof theside wall member with a machine fit.

8. The method of forming a crucible comprising forming a separate sidewall member by machining a portion of the inner wall adjacent one end ofa length of hardened and finished tube to form a taper, forming aseparate bottom member by machining the periphery of a hard-' ened andfinished disc-like member to substantially the same taper as themachined portion or the side wall member, and pressing the bottom memberinto the side wall member with the machine periphery of the bottommember securely engaging the machined portion of the inner wall of theside wall member with a. ma-' chine fit over an area of contactsufilcient to. securely retain the bottom member in position.

9. A crucible comprising a separate tubular side wall member having aportion of the inner wall adjacent one end machined, a separate bottommember comprising a disc-like member the periphery of which is machined,with the bottom member pressed into the side wal1 member with themachined periphery ,of the bottomtmember securelyengaging the machinedportion of the inner wall of the side wall member with chine fit.

10. A crucible comprising a separate tubular graphite side wall memberhaving a portion of the inner wall adjacent one end machined, a separategraphite bottom member comprising a disc-like member the periphery ofwhich is machined, with the bottom member pressed into the side wallmember with the machined periphery of the bottom member securelyengaging the machined portion of the inner wall of the side wall memberwith a machine fit.

11. A crucible comprising a separate tubular graphite side wall memberhaving a portion of the inner wall adjacent one end machined, a separate'graphite bottom member having a fiat lower surface comprising adisc-like member the periphery of which is machined, with the bottommember pressed into the side wall member with the machined periphery ofthe bottom member securely engaging the machined portion of the innerwall of the Side wall member with a ma-. chine fit.

12. A crucible comprising a separate tubular graphite side wall memberhaving a portion of the inner wall adjacent one end machined, a separategraphitebottom member comprising a disc-like member the periphery ofwhich is machined, with the bottom member pressed into the side wallmember with the machined periphery of the bottom member securelyengaging a mathe machined portion'of the inner wall of the side wallmember with a machine fit, the area of contact of the bottom member withthe side wall member being sufilcient to securel retain the bottommember in position.

13. A crucible comprising a separate tubular side wall member having aportion of the inner wall adjacent one end machined to a larger innerdimension, a separate bottom member comprising a disc-like member theperiphery of which is machined, with the bottom member pressed into theside wall member with the machined periphery of the bottom membersecurely engaging the machined portion of the inner wall of the sidewall member with a machine fit.

14. A crucible comprising a separate tubular graphite side wall memberhaving a portion of the inner wall adjacent one end machined to a largerinner dimension, a separate graphite bottom member, comprising adisc-like member the periphery of which is machined, with the bottommember pressed into the Side wall member with the machined peripheryofthe bottom member securely engaging the machined portion of the innerwall of the side wall member withamachineflt.

15. A crucible comprising a separate tubular graphite side wall memberhaving a portion of the inner wall adjacent one end machined to a largerinner dimension, a separate graphite bottom member, comprising adisc-like member the periphery of which is machined with the bottommember pressed into the side wall member with the machined periphery ofthe bottom member securely engaging the machined portion 01 the innerwall of the side wall member with a machine iit, the area of contact ofthe bottom member with the side wall member being suflicient to securelyretain the bottom member in position.

' chined periphery of the bottom membersecurely engaging the machinedportion of the inner wall of the side wall member with a machine fit.

17. A crucible comprising a separate side wall member having a portionof the inner wall adjacent one end machined to form a taper, a separatebottom membercomprising a disc-1ike mem ber the periphery of which ismachined to form approximately the same taper as the machined portion ofthe side wall member, with the bottom member pressed into the side wallmember with the machined periphery of the bottom member securelyengaging the machined portion of the inner wall of the side wall memberwith a machine fit.

.18. A crucible comprising a separate graphite side wall member having aportion of the inner wall adjacent one end machined to form a taper, aseparate graphite bottom member comprising a disc-like member theperiphery of which is machined to form approximately the same taper asthe machined portion of the side wall member, with the bottom memberpressed into the side wall member with the machined periphery of thebottom member securely engaging the machined portion of the inner wallof the side wall member with a machine fit.

19; A crucible comprising a separate graphite side wall member having aportion of the inner wall adjacent one end machined to form a taper, aseparate graphite bottom member comprising a disc-like member theperiphery of which is machined to form approximately the same taper asthe machined portion of the side wall member, with the bottom memberpressed into the side wall member with the machined periphery of thebottom member securely engaging the machined portion of the inner wallof the side wall member with a machine fit, the area of contact of thebottom member with the side wall member being sufiicient to securelyretain the bottom member in position.

ROBERT J. ANICETTI.

REFERENCES CITED The following references are of record in the file ofthis patent:

. UNITED STATES PATENTS France Apr. 13, 1909

